The corrosion inhibition and adsorption behavior of lauryl-imidazoline (IM-11)

1-aminoethyl-2-lauryl-imidazoline (AIM-11) and 1-hydroxyethyl-2-lauryl-imidazoline (HIM-11) were investigated as corrosion inhibitors for Q235 steel corrosion in 3% NaCl solution saturated with CO2 by mass loss and electrochemical polarization curves.The results indicated that the three inhibitors all showed excellent corrosion inhibition performance in CO2 corrosion environment.The inhibition efficiency order of the three inhibitors was HIM-11 > AIM-11 > IM-11.The adsorption was spontaneous and exothermic and followed Langmuir isotherm.It belonged to mix-type adsorption mainly dominated by chemisorption.The relationship between molecular structure and inhibition efficiency was investigated by density functional theory (DFT) of quantum chemical calculations

and the quantitative structure-activity relationship (QSAR) model was established.The adsorption behavior of inhibitor molecules on Fe(001) surface was simulated by the molecular dynamics method.The results showed that the ring imidazole and heteroatoms of the polar group on the hydrophilic chain preferentially adsorbed when the inhibitors reacted with metal surface

and the adsorption stability weakened gradually in the order of HIM-11

AIM-11

IM-11.The theoretical calculation accorded well with experimental results.